A network model for capture of emulsion droplets in porous media

Abstract

Capture of emulsion droplets in porous media can be costly or beneficial. When produced water is injected into reservoir for pressure maintenance, the oil droplets in produced water can plug reservoir rocks and cause the well to lose injectivity. Enhanced oil recovery (EOR) technology takes advantage of this feature and plugs high-injectivity zones with emulsions. Previous studies reveal that interception and straining are the mechanisms of permeability decline. Established models rely on filtration data to determine key parameters. In this work, a network model is proposed to simulate capture of oil droplets in reservoir rocks and resultant permeability reduction. The model is validated with test data and reasonably good results are obtained. The simulation also reveals that the wettability of the tested porous media was altered by injection of emulsions. The new approach considers the characteristics of the porous media and incorporates the damage mechanisms, thus providing more scientific insights into the flow and capture of droplets in porous media.